What Section 508 is
Section 508 is part of the Rehabilitation Act of 1973, strengthened in 1998. It requires federal agencies to make the information and communication technology they develop, buy, maintain or use accessible to people with disabilities, both employees and members of the public. "Information and communication technology" includes electronic documents, not just software and websites.
The technical rules are the Revised 508 Standards, published by the U.S. Access Board in January 2017. Agencies have had to comply with them since 18 January 2018.
Who it applies to
The law binds federal agencies. It reaches everyone else through procurement: when an agency buys a product, a service or a deliverable, the contract usually requires it to conform to the 508 Standards. That is why contractors, grantees and consultants who produce reports for government clients are routinely asked for "508-compliant" files.
Many states have adopted Section 508 or WCAG by reference for their own agencies and universities, so the same expectations often apply to state and local work too.
Which documents are covered
The standards split electronic content into two groups.
Public-facing content: always covered
Anything an agency makes available to the public, whether on a website, as a download or by email, must conform. That includes reports, fact sheets, notices, newsletters and presentation slides.
Internal content: covered when it is official communication
Content that is not public-facing is covered when it is an official agency communication in one of nine categories:
- Emergency notifications
- Initial or final decisions adjudicating an administrative claim or proceeding
- Internal or external program or policy announcements
- Notices of benefits, program eligibility, employment opportunity or personnel action
- Formal acknowledgements of receipt
- Survey questionnaires
- Templates
- Educational or training materials
- Intranet content designed as a web page
Drafts and working files passed between colleagues are generally outside these categories. The finished version that gets published or formally issued is not.
The standard a document must meet
The Revised 508 Standards don't write their own document rules. They incorporate the Web Content Accessibility Guidelines (WCAG) 2.0, Level A and Level AA and apply them to documents as well as web pages. Wherever WCAG says "web page", read "document".
Four WCAG criteria are about navigating between pages of a website, so the standards exempt non-web documents from them:
- 2.4.1 Bypass Blocks
- 2.4.5 Multiple Ways
- 3.2.3 Consistent Navigation
- 3.2.4 Consistent Identification
Everything else in WCAG 2.0 AA applies to a PDF or a Word file just as it applies to a web page.
What that means for a PDF or Word file
In practice, conformance for a document comes down to a short list of things a screen reader, a magnifier or a keyboard user depends on:
| Requirement | Why | WCAG |
|---|---|---|
| Real structure (tags in a PDF, styles in Word) | Headings, lists and tables must be marked as such, not just look like them. | 1.3.1 |
| A logical reading order | Assistive technology reads in the order of the structure, not the layout. | 1.3.2 |
| Alt text for meaningful images | A screen reader can't describe a picture with no text alternative. | 1.1.1 |
| Decorative content marked as such | Borders, background art and repeated headers shouldn't be read aloud. | 1.1.1 |
| Table header cells | So each data cell can be announced with its row and column headers. | 1.3.1 |
| Sufficient contrast | At least 4.5:1 for body text, 3:1 for large text (18 pt, or 14 pt bold). | 1.4.3 |
| Colour is not the only signal | "Items in red are overdue" fails anyone who can't see red. | 1.4.1 |
| A document title and language | The title is what's announced first; the language selects the right voice. | 2.4.2, 3.1.1 |
| Meaningful link text | "Click here" means nothing when a reader lists the links on their own. | 2.4.4 |
| Labelled form fields | Every fillable field needs a name a screen reader can announce. | 1.3.1, 4.1.2 |
A scanned page is the most common outright failure: it is a picture of text with no text in it at all, so nothing above can be applied until it has been run through OCR.
The accessible PDF checklist walks through each item in detail.
Section 508, WCAG 2.1 and the ADA
Section 508 still points at WCAG 2.0. Newer versions, WCAG 2.1 and 2.2, add criteria rather than replacing them, so a document that meets WCAG 2.1 AA also meets 2.0 AA. Many agencies and most accessibility policies outside government now ask for 2.1 AA. The Department of Justice's 2024 rule under Title II of the Americans with Disabilities Act adopted WCAG 2.1 AA for state and local government web content and documents. Targeting 2.1 AA covers both.
For PDFs specifically, there is also PDF/UA (ISO 14289), a technical standard for how an accessible PDF file is built. Section 508 doesn't require it by name, but it is the most precise way to check that a PDF's internal structure is right. See PDF/UA explained.
How to check a document
No single check proves conformance. A sound review combines three things:
- An automated checker, such as Acrobat Pro's accessibility check, Word's built-in Accessibility Checker, or the free PAC (PDF Accessibility Checker) for PDF/UA. These catch missing tags, missing alt text and structural errors quickly.
- A manual review of what software can't judge: whether alt text is accurate, whether heading levels reflect the real outline, and whether the reading order makes sense.
- A pass with a screen reader, such as the free NVDA on Windows. Listening to a document once is the fastest way to find what a checker missed.
Many agencies publish their own testing checklists, and the federal government's Section508.gov site hosts guidance and training. If your contract names a specific test process, follow that one.